Refrigerating system



- PatentedSe'pt. s, 1945 UNITED STATES PATENT OFFICE i REFR IGERATING SYSTEM Irvin-E. Wiegers, Overland, Mo.`, assignor to Milwaukee Gas Specialty Company, Milwaukee,

Wis., a corporation of Wisconsin Application April 23, 1943, Serial No. 484,233

Claims.

This invention relates to refrigerating sys-` cult with past systems to exclude liquid from the suction 'line and inasmucp as the temperature sensitive bulb which controls the functioning of the thermostatic expansion valve is positioned to be influenced by the temperature of ,the refrigerant in the suction line, it is apparent that the presence of liquid in the suction line has a, detrimental efi'ect upon the control of the valve.

In consequence to the periodic passage of "slugs" of liquid refrigerant through the suction line and past the bulb, hunting sets in; that is, successive and abrupt changes in temperature influence on the bulb caused by the "slugs" of, liquidprefrigerant flowing down the suction line, cause repeated opening and closing of the expension valve with a resulting wetting and drying of portions of the evaporator and a constant fluctuatlon in suction pressure.

The purpose of this invention is to overcome this objectionable condition.

More speciflcally, it s an object-of this invention to` provide an improved manner of applyingthe temperature influence of the refrigerant passing from the evaporator to the controlbulb of the thermostatic expansion valve complete example of the' physical embodiment a of the invention'constructed in accordance with the best` mode so !ar devised for the practical fpplication of the principles thereof, and in which? v r Figure 1 is a diagrammatic illustration of a refrigerating system embodying this invention;

Figure 2 is an enlarged detail view illustrating the manner in which the control bulb of the expansion valve is mounted; and

Figura 3 is a detail cross sectional view taken through Figure 2 on the plane of the line 3-3.

Referring now particularly to the accompanying drawing, in which like numerals indicate like parte, the numeral 5 designates the com-` pressor of `a refrigerating system, the inlet of which has a main suction line 6 connected thereto. A pressure line 1 leads from the outlet ot the compressor to a condenser 8. The compressor, as is customary, in conjunction with the condenser reduces the gaseous refrigerant fiowing in the suction line 6 to a liquid.

The 'liquid reirigerant leaving the condenser .8 enters a suitable receiver 9 from which a main liquid refrigerant supply line o leads.

Connected across the main liquid supply line n and the main suction line 6 are evaporator units ll. Obviously, there may be but a single evaporator or as many as the installation requires. The feed line I! of each evaporator which connects with the mam liquid supply line M 'has a thermostatic expansion valve |3 connected therein to regulate the admission of liquid refrigerant into the evaporator. The other end of the evaporator is connected with the main suction line through a discharge or suction line M.

The functioning of the thermostatic expansion I valve l3 is controlled by-a temperature sensitive bulb |5 connected with the valve by' a capillary tube IS. Heretofore this temperature sensitive bulb has been mounted adjacent to the suction line H leading from the evaporator and as a con- 7 sequence whenever a "slug" of liquid refrigerant passed through the suction line, which was in- The present invention overcoines this difliculty by mounting the temperature sensitive control bulb l5 not adjacent to the suction line |4,` but rather in juxtaposition to a branch l'l of the suction line so arranged that only gaseous reirigerant passes therethrough;

In the specific embodiment illustrated. this branch l'l consists of a substantially hairpin shaped loop of` tubing having parallel legs and having its e'nds b'azecl` or otherwise Secured in inlet and outlet ports I! and s.

sitive bulb which effects operation of the valve, characterized by the fact that: the bulb is mounted in juxtaposition to a shuntbranch connected with the suction line; and by a constricis dissuaded from passing into and through the turi throat 2| the extent of the diversion of geseous refrigerant through the shunt branch l 'I can be controlled, as will be readily apparent.

Attention is directed to the fact that the shunt branch l'l has two parallel runs or leg`s and that the control bulb [5 is mounted between them preferably in contact therewith. Thus, the bulb has two areas of contact with the shunt branch to increase the temperature modifying influence of the gaseous refrigerant on the bulb.

It is also preferable to enclose the shunt branch l'l and the bulb l5 in a sheath 22 of suitable heat insul ating material such as sponge rubber, asbestos, or the like.

From the foregoing description. taken in connection with the accompanying drawing, it will be readily apparent to those skiiled in the art that this invention overcomes one of the most troublesome difflculties experienced in refrigerating systems 'by precluding the vacillating eflect on the control bulb of the expansion valve, caused by "slugs" ofliquid refrigerant passing down the suction line. i

What I claim as my invention is:

1. A refrigerating system in which the flow of liquid refrigerant into an evaporatoris controlled by a thermostatic expansion valve having a temperature sensitive bulb for actuating the-same, characterized by the fact that: the bulb is mounted in juqctapositon to a branch of the suction line leading' from the evaporator and connected with the suction line at spaced points and the inlet thereto extending abruptly upwardly from its juncture with the suction line so that the'flow of liquid refrigerant which may be present inthe suction line, through said .branch is discouraged while gaseous rfr'igerant is free to pass through said branch.- i

` 2. A refrigerating systemincluding an evap- -orator having a feed line leading thereto and a suction line leading therefrom'and in which the flow of liquid refrigerant through the feed line and into theevaporator is controlled by' a thermostatic expansion valve having a temperature sensitive bulb which effects operation of the valve, characterized by the fact that:` .the bulb is mounted in juxtaposition to a shunt branch connected with the suction line with the inlet thereof extending abruptly upwardly from the suction line; and by a constriction of the suction line adjacent the juncture of the outlet of said shunt branch with the suction line. whereby the flow of gas through said shunt branch is encouraged.

3. A refrigerating system including an evaporator having a feed line leading thei-eto and a atatic expansion valve having a temperature sention of the suction line adjacent to the juncture of the outlet of'said shunt branch with the suction line, whereby'the flow of gas through said shunt branch ia encouraged; and by the further fact that the shunt branch projects upwardly and substantially at right angles to the suction line so that liquid refrigerant which may be present in the suction line is discouraged from passing into the shunt branch.

4. In a refrigerating system of the type including an evaporator, a feed line for supplying liquid refrigerant to the evaporator, a thermostatic expansion valve in the feed line controlling the flow of liquid refrigerant into the evaporator, said expansion valve having a temperature sensitive bulb by, which the functioning of the valve is controlled. and a suction line leading from the evaporator: a shunt passage connected with the suction'line in a manner forming a branch thereof and with the inlet of said shunt passage sion valve being in Juxtaposition to extending upwardly from and at an abrupt angle to the suction line and means for inducing the flow of refrigerant gases from said suction line into and through said branch, and said temperature sensitive bulb of the expansion valve being mounted in juxtap'osition to said branch to be responsive to the temperature of the gas flowing therethrough. f

5. In a refrigerating system having an evap- .orator from which a suction line leads and having an expansion valve controlling the flow oi liquid refrigerant into the evaporator, said valve having a temperature sensitive bulb controllin'g the operation thereof: a shunt branch connected with the section line with the inlet of the shunt branch forming an abrupt upward angle to the suction line: the temperature sensitive bulb of the expa'nsion valve being in juxtaposition to the shunt branch to be influenced by the temperature of refrigerant gases flowing through said shunt branch; 'and a constriction in the suction line between its junctions with the shunt branch and near the outlet of the shunt branch for inducing' a flow of refrigerant gas 'through said shunt branch.

6. In a refrigerating system having an evaporator from which a suction line leads and having an expansion valve controlling the flow of liquid, refrigerant into the evaporator, said valve having a temperature sensitive bulb controlling the operation thereof: a shunt branch connected with the suction line with the inlet of the shunt branch forming an abrupt upward angle with the suction line; the temperature sensitive bulb ot the expanthe shunt branch to be influenced by. the temperature' of refrigerant gases flowing through said shunt branch; and a Venturi throat in the suction line adjacent to the point of discharge of the shunt branch for inducing the flow of refrigerant gas through the shunt branch.

7. In a refrigerating system having an evaporator adapted to be fed with liquid refrigerant v control bulb: a branch ine connected with the I suction line and extending at an upward angle therefrom so that gases in the suction line readily flow into and through the branch line while &s emes any liquid present in the suction iine fiows past the branch without enteringit: and said control and from 'which a suction line leads and having.

a thermostatic expansion vaive controlling the flow oi liquid refrigerant into the evapoi'ator. the expansion valve having a temperature sensitive control-bulb: 'a branch line having its inlet connected with the suction line et one point and its outlet connected with the suction line downstream from said point. the hranch iine having a portion thereo between its iniet and 'outiet disposed at an eievation higher than the point at which the inlet connects with the suction line so that gases in the suction line readily flow into and through the hranch line while any liquid present in the suction line is dissuaded from entering mission of iiquid reirigerant into the evsporator, the expansion vaive having a temperature sensitive controibulb: a iooped branch line connected with the suction line to provide a, parallei passage for refrigerant flowing through the suction line. said *looped branch having closely adjacent spaced runs extending upwardiy from the suction line; and the temperature sensitive buib of the expansion vaive being mou'nted in juxtaposition e to said closeiy adjacent runs so as to be. in-

said portion of the brench line: said control bulb being mounted in juxtaposition to said portion of the branch line to be infiuenced by the temperatureof the gases flowing the'ethrough; and a constriction in the suction line between its Junc- 9. In a refrigerating system having an evaporator adapted to be -feri with liquid refrige'ant spaced runs extending upwardiy from the suction line; the temperature sensitive bulb of the expenand from which a suction line leads and having a fluenced by the temperature of the rerrigerator `fiowing therethrough.

10. In a refrigerating system having an even- V ogator adapted to be ed with liquid retrigerent and from which a suction line leads and having e.

thermostatic expansion valve controlling the adwith the suction line to provide a parailei pas- V sage tor reirigerant flowing through the suction line, said looped branch having closely adjacent sion valve being mounted in iuxtaposition to said' cioseiy adjcent runs so as to be influenced by the temperature of the refrigerant flowing therethrough; and an insulating sheath enciosing the branch ime and the bulb to protect the same from influence by ambient temperature changes.

mvn E. Wiliams.

thermostaticexpansion valve controiiing the sd- 

